A method for planarizing metal interconnects of a semiconductor wafer includes the steps of polishing the semiconductor wafer with a polishing solution and a polishing pad to planarize the metal interconnects. The polishing solution has by weight percent, 0.15 to 5 benzotriazole, 0 to 1 abrasive, 0 to 10 polymeric particles, 0 to 5 polymer-coated particles and balance water at a pH of less than 5 and a removal rate-pressure sensitivity (dr/dp) of at least 750 (Å/min/psi). The polishing simultaneously accelerates removal of projecting metal from the metal interconnects with the polishing pad providing a first pressure that increases removal rate of the projecting metal; and it inhibits removal of recessed metal from the metal interconnects with the polishing pad providing a second pressure that decreases removal of the recessed metal.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method for planarizing metal interconnects of a semiconductor wafer comprising the steps of: a) polishing the semiconductor wafer with a polishing solution and a polishing pad to planarize the metal interconnects, the metal interconnects being a nonferrous metal selected from the group consisting of copper, copper-base alloys, silver and silver-base alloys and the polishing solution having by weight percent, 0.15 to 5 benzotriazole, 0 to 1 abrasive, 0 to 10 polymeric particles, 0 to 5 polymer-coated particles and balance water at a pH of less than 5 and a removal rate-pressure sensitivity d r /d p of at least 750 Å/min/psi; b) accelerating removal of projecting metal from the metal interconnects with the polishing pad providing a first pressure that increases removal rate of the projecting metal; and c) inhibiting removal of recessed metal from the metal interconnects with the polishing pad providing a second pressure that decreases removal of the recessed metal and wherein the accelerating and inhibiting steps occur in a simultaneous manner.
2. The method of claim 1 wherein the polishing follows a first-step polishing step that removes a top layer of the metal interconnects.
3. The method of claim 1 including the additional step of finishing the metal interconnects by polishing at a reduced pressure with the polishing solution of step a) to remove residual nonferrous metal from the metal interconnects.
4. The method of claim 1 wherein the polishing solution has a removal rate-pressure sensitivity of least 1,000 Å/min/psi to reduce dishing of the metal interconnects during the polishing.
5. The method of claim 1 including the additional step of complexing the nonferrous metal removed from the metal interconnects.
6. A method for planarizing metal interconnects of a semiconductor wafer comprising the steps of: a) polishing the semiconductor wafer with a polishing solution and a polishing pad to planarize the metal interconnects, the metal interconnects being a nonferrous metal selected from the group consisting of copper, copper-base alloys, silver and silver-base alloys and the polishing solution having by weight percent, 0.2 to 2 benzotriazole, 0 to 20 oxidizer, 0 to 20 complexing agent, 0 to 0.5 abrasive, 0 to 5 polymeric particles, 0 to 2.5 polymer-coated particles and balance water at a pH of less than 4 and a removal rate-pressure sensitivity d r /d p of at least 1000 Å/min/psi; b) accelerating removal of projecting metal from the metal interconnects with the polishing pad providing a first pressure that increases removal rate of the projecting metal; and c) inhibiting removal of recessed metal from the metal interconnects with the polishing pad providing a second pressure that decreases removal of the recessed metal and wherein the accelerating and inhibiting steps occur in a simultaneous manner.
7. The method of claim 6 wherein the polishing follows a first-step polishing step that removes a top layer of the metal interconnects.
8. The method of claim 6 including the additional step of finishing the metal interconnects by polishing at a reduced pressure with the polishing solution of step a) to remove residual nonferrous metal from the metal interconnects.
9. The method of claim 6 wherein the nonferrous is selected from the group consisting of copper and copper-base alloys and the polishing solution has a removal rate-pressure sensitivity of least 1,500 Å/min/psi to reduce dishing of the metal interconnects during the polishing.
10. The method of claim 6 including the additional step of complexing the nonferrous metal removed from the metal interconnects.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
March 28, 2003
August 30, 2005
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